1. Field of the Invention
The invention is related to the field of communications, and in particular, to communications between antennas, base stations, and service nodes.
2. Description of the Prior Art
FIG. 1 illustrates communication system 100 in an example of the prior art. Communication system 100 includes antenna 103, base station 104, and service node 105. Both antenna 103 and base station 104 are located at the same site 106. In most cases, site 106 represents an elevated structure, such as a building or tower.
Antenna 103 exchanges user communications in a wireless communication format with wireless communication devices 101-102 over wireless communication links 111-112. The wireless communication format could be Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), or some other wireless communication format. Thus, site 106 (antenna 103 and base station 104) provides wireless communication service to devices within an area defined by cell 107.
Antenna 103 exchanges the user communications with base station 104 over communication link 113. Communication link 113 is typically a relatively short metallic connection. Base station 104 exchanges the user communications with service node 105 over communication link 114. Communication link 114 is typically a Time Division Multiplex (TDM) connection, such as a T1 or DS3. Service node 105 processes the user communications to provide a communication service, such as telephony or Internet access, to wireless communication devices 101-102.
As the demand for wireless communications increases, antenna 103 and base station 104 eventually do not have the capacity to serve all potential users. To add capacity, cell 107 is split into two cells, where antenna 103 and base station 104 serve one split cell, and a new antenna and base station are installed at a new site to serve the other split cell. FIG. 2 illustrates the resulting spilt-cell communication system.
FIG. 2 illustrates communication system 200 in an example of the prior art. Communication system 200 includes antennas 103 and 203, base stations 104 and 204, and service node 105. Note that former cell 107 (See FIG. 1) has been split into two cells 207 and 208. Existing site 106 retains existing antenna 103 and existing base station 104 to serve new cell 207. New site 206 includes new antenna 203 and new base station 204 to serve new cell 208. In most cases, sites 106 and 206 represent elevated structures, such as buildings or towers.
Existing antenna 103 exchanges first user communications in a wireless communication format with wireless communication device 101 over wireless communication link 111. Existing antenna 103 exchanges the first user communications with existing base station 104 over existing communication link 113. Existing base station 104 exchanges the first user communications with existing service node 105 over existing communication link 114. Existing service node 105 processes the first user communications to provide the communication service to wireless communication device 101.
New antenna 203 exchanges second user communications in a wireless communication format with wireless communication device 102 over wireless communication link 211. New antenna 203 exchanges the second user communications with new base station 204 over new communication link 213. New base station 204 exchanges the second user communications with existing service node 105 over new communication link 214. Existing service node 105 processes the user second communications to provide the communication service to wireless communication device 102.
New cell 208 requires a new site 206 to house new antenna 203 and new base station 204. Thus, new site 206 must have enough space to accommodate both new antenna 203 and new base station 204. Since new site 206 is typically on an elevated structure, the elevated structure must have enough space to accommodate both new antenna 203 and new base station 204.
Unfortunately, an elevated structure that is properly located to serve cell 208 and that has enough space for a new antenna and base station may be hard to find and may be very expensive. In addition, new communication link 214 is required from new site 206 to service node 105, and new communication link 214 is typically an expensive TDM link. Thus, new site 206 may be very difficult or impossible to find, and new site 206 may become prohibitively expensive to implement.
Surface wave transmission systems have become available from suppliers, such as Coridor. Surface wave transmissions are guided microwave radio frequencies from approximately 800 MHz to 10 GHz whose properties enable their propagation as guided waves following a conductor path. In a surface wave transmission system, a first surface wave interface exchanges communication signals with a second surface wave interface over an electrical power line—possibly the power line neutral or a powered alternating current distribution line. The communication signals are transferred in the form of an electromagnetic wave that propagates externally to and around the surface of the power line as a guided Radio Frequency (RF) wave. In some cases, surface wave transceivers are doughnut-shaped around the power line, and they propagate doughnut-shaped electromagnetic waves around and along the external surface of the power line. Unfortunately, surface wave technology has not been effectively implemented to alleviate the split cell problem described above.